The present invention is concerned with a device which senses vibration in case abnormal vibration such as that associated with an earth quake has happened and which works to start a corresponding function.
With regard to, for example, earth quakes, it is reported that the vibration which exceeds a certain value, i.e., which exceeds about 80 gal in terma of acceleration (seismic coefficient 5) may give damage to human beings and animals. It is also reported in the past earth quake statistics that the frequency of vibration of the earth quake ranges from 1 HZ to 5 HZ. It is, therefore, required for the quake-sensing starting device to have uniform and reliable performance to sense vibrations over the entire wide range of from 1 HZ up to, for example, 5 HZ. Many of the earlier quake-sensing starting devices, however, were, on the one hand, sensitive to some particular frequency ranges of the vibration but were not, on the other hand, sensitive to other frequency ranges of the vibration. For example, with a conventional vibration-sensing mechanism shown in FIG. 3, the separator plate 1 interposed between the lower surface of a magnet 2 and the upper surface of a steel ball 3 was of uniform thickness, in which the distance between the two was always uniform even at the central portion or at the peripheral portions whereby the intensity of the magnetic force of the steel ball 3 was the same regardless of the displacement of the steel ball 3. Particularly, in the lower frequency ranges, the steel ball 3 could not roll below the lower surface of the separator plate 1 to get out of the magnetic force; the steel ball 3 would not often fall to start the reporting or alerting function.
On the other hand, the mounting angle of a handle of valves or cocks which shuts off the passage of liquid is seldom placed just horizontal but is largely tilted, as could be recognized from the household propane gas containers that are usually just out of right-angled position. Therefore, where the vibration-sensing starting device of the type in which the weight is hung by way of a magnet and falls upon sensing the vibration, was mounted on the aforesaid object bodies, the lower surface of the magnet was inclined and the weight was not stably absorbed, and further, the weight often failed to operate reliably.
The first object of the present invention, therefore, is to provide a quake-sensing starting device which has minimized the aforementioned defects and which can sensitively and reliably respond to any low, middle and high frequency ranges, so that the weight falls down overcoming the magnetic force to start the sensing function.
The second object of the present invention is to provide a quake-sensing device which has improved the aforementioned defects and which can keep the vibration-sensing part at a horizontal relation by correcting the deviation even where the object body is installed on an inclined position, to ensure reliable functioning of the device.